Final answer:
The spinothalamic tract and dorsal column system are the two major tracts in the spinal cord for pain and temperature sensation. The spinothalamic tract crosses over in the spinal cord, while the dorsal column system crosses over in the medulla of the brain stem.
Step-by-step explanation:
The two major tracts in the spinal cord for pain and temperature sensation are the spinothalamic tract and the dorsal column system. The spinothalamic tract is responsible for carrying pain and temperature information from the body to the brain. The information in this pathway crosses over in the spinal cord at the level of entry. On the other hand, the dorsal column system primarily carries information about touch and proprioception and crosses over in the medulla of the brain stem.